This invention relates generally to electronically commutated motors (ECMs), and more particularly, to methods and apparatus for controlling electronically commutated motors.
Some known blower motors are designed to operate at a single speed. However, due to the energy saving benefits of operation at low speed and the need to overcome high static pressures at high speed, blower motors included in air moving systems, such as heating, ventilation and air conditioning (HVAC) systems, often operate over a wide range of speeds. Therefore, since variable speed electronically commutated motors are more efficient than known standard induction motors, air moving systems, such as HVAC systems, often include ECMs. Typically, air moving system controller circuits operate at a different voltage level than the ECM, and an electrical interface is required for the controller to communicate with the ECM. Such interfaces typically control the ECMs using pulse width modulation (PWM) by continuously adjusting motor speed. Because such interfaces communicate using PWM, the interfaces are often complex and expensive.
In one aspect of the invention, a method is provided for controlling an electronically commutated motor (ECM) using an air moving system including a controller and an interface board, the interface board electrically coupled to the air moving system controller. The ECM electrically coupled to the interface board. The ECM includes a motor controller having an ECM program and the interface board includes a mode signal circuit and a tap signal circuit. The method includes transmitting control signals to the interface board, translating the signals into signals suitable controlling the ECM, and operating the ECM based on the translated signals.
In another aspect of the invention, a system is provided for controlling an ECM. The system comprises a controller, an interface board electrically connected to the controller, and an ECM electrically connected to the interface board. The system is configured to transmit control signals to the interface board, translate the signals into signals suitable for receipt by the ECM, and operate the ECM based on the translated signals.
In yet another aspect of the invention, an interface board is provided for controlling an ECM. The interface board electrically coupled to the ECM and a controller. The interface board comprises a mode signal circuit, a tap signal circuit, and a regulating circuit electrically connect to the mode signal circuit and the tap signal circuit. The interface board configured to receive control signals from a controller and translate the signals into signals suitable for controlling the ECM.